In recent years, a cutting tool having a longer tool life than in the case of a conventional cutting tool has been required, along with the improvement of highly efficient cutting. Thus, in terms of the performance required for tool materials, improvements of wear resistance and fracture resistance, which are directly related to the tool life, have been becoming increasingly important. In order to improve such characteristics, a coated cutting tool is used in which coatings are laminated in an alternating manner on a surface of a substrate.
Various techniques have been proposed in order to improve the characteristics of the above-described alternating laminate coatings. For example, Japanese Patent No. 5817932 proposes a coated cutting tool which comprises a first laminate structure in which layers are laminated in an alternating manner with the average thickness of each layer being from 60 nm or more to 500 nm or less and a second laminate structure in which layers are laminated in an alternating manner with the average thickness of each layer being from 2 nm or more to less than 60 nm.